Relax... you have found a reliable extension builder in SL1. M & A UK Ltd is a friendly and reliable company based in SL1 who consider no job as to...
Member since July 2020
EB Construction & Building Ltd are here to help customers who need an Extension Builder in SL1. We offer a competitive rate to complete all your ex...
Need to find an Extension Builder near you for all your extension buildering work?
Mamma V's Caribbean and English Cuisine provides a local...
JJSR Construction Ltd is an established and experienced local extension builder in SL1. Please contact us for a free, no obligation quote and compe...
In an unstable market house extensions are often the most viable option, helping you to get the most out of the space you have without the addition...
Reliable and experienced extension builders with competitive rates and good at keeping within budget. Happy to provide examples of extension builde...
Member since August 2026
Relax... you have found a reliable extension builder in SL1. ABC Associates STRUCTURES 4 U is a friendly and reliable company based in SL1 who cons...
Newpark Construction are here to help customers who need an Extension Builder in SL1. We offer a competitive rate to complete all your extension bu...

Underpinning ranges from £17,500 (EB Construction & Building Ltd based in HP2) to £19,820 (Reid and Co Developments Ltd based in NW8), but the final cost will depend on the method of underpinning used, how much of your foundations need underpinning and where you live.
Comparing extension builders estimates for underpinning gives you an idea of who will be better value but the best way to compare costs is to get actual quotes.
Get quotes to underpin your home in SL1 by posting a job with HaMuch and we will send it to extension builders in SL1.
| Location in UK | Hourly Rate | Daily Rate |
|---|---|---|
| Underpin A Building near Slough | £42 | £272 |
| Underpin A Building near Windsor & Maidenhead | £42 | £272 |
| Underpin A Building near Windsor | £41 | £271 |
| Underpin A Building near Maidenhead | £41 | £273 |
| Underpin A Building near Gerrards Cross | £43 | £282 |
| Underpin A Building near Egham | £42 | £266 |
| Underpin A Building near Staines-upon-Thames | £42 | £269 |
| Underpin A Building near Hillingdon | £63 | £276 |
| Underpin A Building near Ascot | £41 | £276 |
| Underpin A Building near Bracknell Forest | £41 | £287 |
Whether you’re looking to extend your kitchen with a side return extension or you want to convert your basement into a liveable space, read our cost guides to get an idea of how much each project costs before getting a more accurate quote from our database of reliable tradespeople.

Underpin a building - £17,938

Two storey extension - £88,658

Build a timber frame extension - £26,438

Build a swimming pool - £81,438

Single storey extension - £63,768

Side return extension - £46,432

Install an RSJ - £2,638

Outbuilding - £10,438

Build a Mansard loft conversion - £52,438

Loft conversion - £37,860

Build a kitchen extension - £42,438

Hip to gable loft conversion - £42,438

Granny annexe - £87,438

Garden office - £10,438

Convert a Garage - £16,438

Garage - £18,938

Build a flat roof extension - £22,438

Build a dormer loft conversion - £42,438

Concrete foundations - £6,688

Convert a bungalow loft - £29,438

Convert a basement - £42,432